Untitled

use Drupal\Core\Database\Database;

/**
 * Implements hook_help() to test the second database connection.
 */
function mymodule_help($route_name, $route_match) {
  if ($route_name == 'help.page.mymodule') {
    $connection = Database::getConnection('default', 'wordpress');
    try {
      $result = $connection->query('SHOW TABLES')->fetchAll();
      return 'Successfully connected to the WordPress database. Tables: ' . implode(', ', array_map(function($row) {
        return current((array) $row);
      }, $result));
    } catch (Exception $e) {
      return 'Failed to connect to the WordPress database: ' . $e->getMessage();
    }
  }
}